1. Field of the Invention
The present invention relates to image forming apparatuses such as copiers, facsimiles, and printers, and particularly to an image forming apparatus having a recording medium determination device.
2. Description of the Related Art
Image forming apparatuses such as copiers, facsimiles, printers, and printing equipment have been widely used for recording, based on image information, onto recording media such as recording paper. In response to market demands and technical advances made in image forming apparatuses (recording equipment), a variety of recording media have been developed and put into practical use these days. Examples of such recording media include thin paper such as recording paper coated with an ink-absorbing layer to achieve improved image quality, heavy paper such as postcards, plastic sheets, and printable fabric. Typical image forming apparatuses (recording apparatuses), among those capable of recording onto such a variety of recording media, are inkjet printers that form images by spraying ink through nozzles.
Since ink placed on recording media exhibits different degrees of blurring and brightness of colors depending on the type of media, the amount of ink and the number of ink dots are determined based on the type of recording media to achieve the best image quality. They are normally determined by the user's selection of the type of media through the use of setting functions in host computers or printers. An increase in the number of types of recording media leads to an increase in options of the user's selection, and thus adds complexity to the operation. Moreover, since printers do not give warnings in response to the erroneous selection by the user, the use of paper capable of producing high quality images may produce images with low quality.
Additionally, if a printer, such as a network printer shared by a plurality of users, is located remote from a user, the user needs to go to the printer to check the types of recording media held in recording medium storage unit in order to subsequently select the type of recording media to be used for printing. To eliminate such inefficiency and solve the other problems described above, a variety of determination devices for detecting the type of recording media are proposed in, for example, Japanese Patent Laid-Open No. 2-138805, Japanese Patent Laid-Open No. 10-198174, Japanese Patent Laid-Open No. 2-56375, and Japanese Patent Laid-Open No. 6-56313.
However, each of the determination devices disclosed in these patents documents requires a carrier for conveying recording media to maintain a certain distance between a recording medium detector and the recording media, thereby causing an increase in the size of the entire apparatus. Moreover, since these recording medium detectors cannot trace vertical and horizontal curling and deflection of recording media, they cannot consistently perform proper detection. Other concerns include scratches on recording media and operation noise of the apparatus when the recording medium detector comes into contact with the media.